Deflection Differences Between Identical Shafts - Opinions?

ShootingArts said:
I am not expert with all of the new wonder shafts but I have turned a few shafts and was involved with carbon fiber once upon a time.

The lay up should be pretty close to identical dealing with carbon fiber. The batch of resin, not so much so, the cure, subject to manufacturing variances. There is another issue, unless someone is manufacturing these blanks with quality control focused on the characteristics of pool cues, the manufacturer may not even be testing for the things that concern a pool player.

If you are talking about wood splice shafts, you have the basic issues with glues and adhesives plus spliced shafts came to be to use up shaft blanks that were too poor to turn as one piece shafts. Aside from wood quality questions, years ago the manufacturers had issues with radial consistency. This was found with broken shafts and I think at least some destructive testing. Are these issues completely behind the major players? I don't know. They aren't going to admit QC issues if they exist.

As has already been said, you will ultimately have to do your own testing but if I were gambling I would bet that in six months time after having three near identical shafts made you will be playing with one and two will be gathering dust.

Hu
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You are absolutely correct. There is the accuracy of the test setup and the variable of the object being tested.

Test setup could be made pretty accurate with a cylinder like a bimba and then you will only have to measure deflection. This can be done with a strain gauge for best results or use an optical method that is less accurate.

Anytime you have epoxy, layered pieces and inherent inconsistent material like wood you are going to get variance in manufacturing.

The key is if the variance is higher than the user's ability to perceive it.

Last point, anytime you add length to a beam of consistent geometry you change the deflection.
 
knifemakermike said:
...anytime you add length to a beam of consistent geometry you change the deflection.
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This may be true for deflection of the beam (shaft), but I don't believe it's true for CB deflection (squirt), which is determined by the front several inches of the shaft regardless of what's behind that.

pj
chgo
 
I Got Lucky said:
Well i would think if the tips are not shaped the same the ball wont go in the exact same direction. Not sure if its deflection or because if different shaped/angled tips.
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Actually it's neither. Tip shape doesn't affect squirt (if you hit the same CB spot).

It can, however, affect where you hit the CB (compared with where the center of your shaft is pointed) - but that's a tiny difference, probably smaller than your stroke inconsistency.

pj
chgo
 
S.Vaskovskyi said:
My guess OP has shafts made out of solid wood so no layered pieces in the equation;)
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He said it's not a solid shaft. Even if it was wood is notorious for being porous and not consistent. Why do you think they dry it out, it absorbs moisture and the same piece dried out differently will behave differently.
 
Patrick Johnson said:
This may be true for deflection of the beam (shaft), but I don't believe it's true for CB deflection (squirt), which is determined by the front several inches of the shaft regardless of what's behind that.

pj
chgo
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That only would be true if the first several inches were fixed and a perfect cylinder. That's not the case because the whole shaft deflects, I can model it in CAD and run an FEA but it will change deflection point. The question is by how much and is it relevant enough to change the squirt that a player would notice.
 
Patrick Johnson said:
Actually it's neither. Tip shape doesn't affect squirt (if you hit the same CB spot).

It can, however, affect where you hit the CB (compared with where the center of your shaft is pointed) - but that's a tiny difference, probably smaller than your stroke inconsistency.

pj
chgo
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this is my simulation of a straight force load on a 30" shaft vs 29", I didn't spend a ton of time as I have a real job to do but there is clear difference in the stress even at the tip.

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ChrisinNC said:
Mezz EXPro wood shaft with hybrid carbon core and EX front end technology - whatever that means.
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After some other threads I had an idea what shafts are in play here;).
When it comes to your question I guess untill you keep all three of your shafts the same when it comes to the taper with the same tips the difference between them (especially those two 29" shafts) should not be such dramatic making it a big problem to get used to it quickly enough when you have to use a spare shaft. When it comes to using 60" set up (29" shaft) on a 9-footer and 61" (30" shaft) on 10-footer I would stick with the same set up whatever is more comfortable for you. Your height is close to mine (6,5). Most of the years I've played using 60" cue equal split and I was fairly comfortable with that length till I started to experience some problems and pain in my neck and spine a few years ago. I used to try a longer set up (my 60" cue + 6,5" butt extension) but at the end I decided to build a 62" cue (https://forums.azbilliards.com/showthread.php?t=463154). I already knew with my height this length is enough to reach for any shot I may be faced on a 9-foot table especially bearing in mind I'm ok to play left handed when there is a need. For the time being I'm happy with my set up especially when it comes to rotation games where you have to move the CB much more then in straight pool. The only shorter set up I liked a lot was with my current 31" full spliced butt + Revo shaft (60" set up) which I had possibility to try.
So if you're more comfortable with your 60" set up than I would use it on any table plus I would get one more longer butt extension just to use on some shots to reach. If 61" set up is what you feel better with than you have two options to make this set up: your current version 30" shaft + 29" butt + 2" butt extension or another option 29" + 29" shaft and butt + 3" butt extension. Nobody but you can find out what feels and works best for you so I wish you to find that set up.
 
knifemakermike said:
this is my simulation of a straight force load on a 30" shaft vs 29", I didn't spend a ton of time as I have a real job to do but there is clear difference in the stress even at the tip.
[snip really cool pics of science-y stuff]
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I'll take your word for it.

pj
chgo
 
knifemakermike said:
this is my simulation of a straight force load on a 30" shaft vs 29", I didn't spend a ton of time as I have a real job to do but there is clear difference in the stress even at the tip.
Click to expand...


Some cool stuff! A friend used to model some things on a shooting forum. Interesting stuff there too.

I think you have real potential for the aiming forum. If you can't confound them with wisdom you can baffle them with bullshit! They will never know the difference. :thumbup:

Hu
 
Exact same weight on the shafts? Exact same tip? Exact same length of the tip? Exact same shape of the tip?

Try this - prior to the finals of the DCC nine ball tell one of the players he can't use the shaft he played the entire tournament with and hand him an identical shaft. Go up to a player and his backers in a money game and do the same thing.
 
alstl said:
Exact same weight on the shafts? Exact same tip? Exact same length of the tip? Exact same shape of the tip?

Try this - prior to the finals of the DCC nine ball tell one of the players he can't use the shaft he played the entire tournament with and hand him an identical shaft. Go up to a player and his backers in a money game and do the same thing.
Click to expand...

Alstl,

You should know better than to bring common sense into a thread "like this one". Your just gonna confuse folks with reality.
 
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